Abstract
Antisera raised against the major hydroxyproline-rich glycoprotein (HRGP) in carrot (Daucus carota L.) taproot, extensin-1, and a minor HRGP, extensin-2, were characterized by western blot analysis, enzyme-linked immunosorbent assay, and periodate oxidation and found to be directed against carbohydrate epitopes shared by both glycoproteins. The anti-extensin-1 antibodies (gE1) target periodate-sensitive epitopes and may recognize the terminal alpha-1,3-arabinoside of extensin-1. The anti-extensin-2 antibodies (gE2) recognize periodate-insensitive epitopes, possibly binding the reducing, internal beta-1,2-arabinosides on the carbohydrate side chains. Despite the cross-reactivity of these antibodies, immunolocalization studies of carrot taproot and green bean (Phaseolus vulgaris L.) leaf tissues reveal a spatial segregation of gE1- and gE2-labeling patterns. The gE1 antibodies bind only to the cellulose-rich region of the cell wall (J.P. Staehelin and L.A. Stafstrom [1988] Planta 174: 321-332), whereas gE2 labeling is restricted to the expanded middle lamella at three cell junctions. Periodate oxidation of nonosmicated, thin-sectioned tissue abolishes gE1 labeling but leads to labeling of the entire cell wall by gE2, presumably as a result of unmasking cryptic epitopes on extensin-1 in the cellulose layer. Purified extensin-2 protein is more efficient than extensin-1 protein at agglutinating avirulent Pseudomonas strains lacking extracellular polysaccharide. Our results indicate that extensin-2 does not form a heterologous HRGP network with extensin-1 and that, in contrast to extensin-1, which appears to serve a structural role, extensin-2 could participate in passive defense responses against phytopathogenic bacteria.
Full Text
The Full Text of this article is available as a PDF (3.7 MB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Cheresh D. A., Reisfeld R. A., Varki A. P. O-acetylation of disialoganglioside GD3 by human melanoma cells creates a unique antigenic determinant. Science. 1984 Aug 24;225(4664):844–846. doi: 10.1126/science.6206564. [DOI] [PubMed] [Google Scholar]
- Corbin D. R., Sauer N., Lamb C. J. Differential regulation of a hydroxyproline-rich glycoprotein gene family in wounded and infected plants. Mol Cell Biol. 1987 Dec;7(12):4337–4344. doi: 10.1128/mcb.7.12.4337. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Keller B., Lamb C. J. Specific expression of a novel cell wall hydroxyproline-rich glycoprotein gene in lateral root initiation. Genes Dev. 1989 Oct;3(10):1639–1646. doi: 10.1101/gad.3.10.1639. [DOI] [PubMed] [Google Scholar]
- Keller B., Templeton M. D., Lamb C. J. Specific localization of a plant cell wall glycine-rich protein in protoxylem cells of the vascular system. Proc Natl Acad Sci U S A. 1989 Mar;86(5):1529–1533. doi: 10.1073/pnas.86.5.1529. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Laemmli U. K. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature. 1970 Aug 15;227(5259):680–685. doi: 10.1038/227680a0. [DOI] [PubMed] [Google Scholar]
- Lamport D. T., Katona L., Roerig S. Galactosylserine in extensin. Biochem J. 1973 May;133(1):125–132. doi: 10.1042/bj1330125. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leach J. E., Cantrell M. A., Sequeira L. Hydroxyproline-rich bacterial agglutinin from potato : extraction, purification, and characterization. Plant Physiol. 1982 Nov;70(5):1353–1358. doi: 10.1104/pp.70.5.1353. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mauch F., Staehelin L. A. Functional Implications of the Subcellular Localization of Ethylene-Induced Chitinase and [beta]-1,3-Glucanase in Bean Leaves. Plant Cell. 1989 Apr;1(4):447–457. doi: 10.1105/tpc.1.4.447. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Mellon J. E., Helgeson J. P. Interaction of a hydroxyproline-rich glycoprotein from tobacco callus with potential pathogens. Plant Physiol. 1982 Aug;70(2):401–405. doi: 10.1104/pp.70.2.401. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Showalter A. M., Bell J. N., Cramer C. L., Bailey J. A., Varner J. E., Lamb C. J. Accumulation of hydroxyproline-rich glycoprotein mRNAs in response to fungal elicitor and infection. Proc Natl Acad Sci U S A. 1985 Oct;82(19):6551–6555. doi: 10.1073/pnas.82.19.6551. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Showalter A. M. Structure and function of plant cell wall proteins. Plant Cell. 1993 Jan;5(1):9–23. doi: 10.1105/tpc.5.1.9. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Stiefel V., Ruiz-Avila L., Raz R., Pilar Vallés M., Gómez J., Pagés M., Martínez-Izquierdo J. A., Ludevid M. D., Langdale J. A., Nelson T. Expression of a maize cell wall hydroxyproline-rich glycoprotein gene in early leaf and root vascular differentiation. Plant Cell. 1990 Aug;2(8):785–793. doi: 10.1105/tpc.2.8.785. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Woodward M. P., Young W. W., Jr, Bloodgood R. A. Detection of monoclonal antibodies specific for carbohydrate epitopes using periodate oxidation. J Immunol Methods. 1985 Apr 8;78(1):143–153. doi: 10.1016/0022-1759(85)90337-0. [DOI] [PubMed] [Google Scholar]
- Ye Z. H., Varner J. E. Tissue-Specific Expression of Cell Wall Proteins in Developing Soybean Tissues. Plant Cell. 1991 Jan;3(1):23–37. doi: 10.1105/tpc.3.1.23. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van Holst G. J., Varner J. E. Reinforced Polyproline II Conformation in a Hydroxyproline-Rich Cell Wall Glycoprotein from Carrot Root. Plant Physiol. 1984 Feb;74(2):247–251. doi: 10.1104/pp.74.2.247. [DOI] [PMC free article] [PubMed] [Google Scholar]